An integrated circuit is typically fabricated by processing various thin films on a substrate. The thin films are usually formed, for example, through etching, ion implantation, and chemical mechanical polishing processes. During the above processes, contaminants such as sidewall polymers or fences may be produced, often as a result of the reaction between a conductive layer, a photoresist, and an etching gas typically used to process the conductive layer (e.g., an aluminum layer, a titanium layer, an aluminum-silicon layer, a tungsten layer, a tungsten-titanium layer, and a titanium-nitride layer). As a result, the yield and reliability of the ultimate product may be adversely impacted. Additionally, as the integration level of integrated circuit devices increases along with heightened production speeds, the presence of the above-mentioned contaminants may be disadvantageous. In view of the above, there is a perceived need to more effectively remove the contaminants from the devices.
FIGS. 1 and 2 describe a conventional cleaning method subsequent to: (1) a step for forming a contact hole which exposes a conductive layer by dry etching or (2) a step for patterning a conductive layer. Reference numeral 10 denotes a integrated circuit substrate such as a semiconductor substrate, reference numeral 20 denotes an interlayer insulation layer, reference numeral 30 denotes a conductive layer, reference numeral 30A denotes a conductive layer pattern, reference numeral 40 denotes an oxide layer, reference layer 50 denotes a contact hole, and reference numeral 60 denotes a contaminant. In particular, FIG. 1 illustrates semiconductor substrate 10 having a contact hole 50 formed thereon, which is conventionally cleaned with a photoresist stripper or an organic stripper.
Typically, contaminants such as etching-residues are removed from the sidewalls and bottom of the contact hole 50 by dipping the integrated circuit substrate in the conventional cleaning solution at a temperature ranging from 60.degree. C. to 90.degree. C. The conventional cleaning solution remaining on the surface of the semiconductor substrate may be removed by dipping the integrated circuit substrate into an alcohol-containing rinser, and then dipping the substrate into deionized water. Next, contaminants remaining on the surface of the integrated circuit substrate can be removed by dipping the substrate into a second deionized water bath. Thereafter, the substrate is usually spun to remove deionized water remaining on the surface of the substrate.
A number of problems may be associated with using a conventional cleaning solution. A conventional cleaning solution such as a photoresist stripper or an organic stripper may be limited in its ability to remove etching residues or other contaminants which can adhere to a surface of a contact hole. As a result, the cleaning may not be effective, and a portion of contaminant 60 can remain on the sidewalls and bottom of the contact hole as shown in FIG. 1. In particular, organometallic sidewall polymers are often oxidized into oxo-metallic complexes by a process of plasma ashing which is carried out in order to remove a photoresist. It is often difficult to effectively remove these oxo-metallic complexes using conventional cleaning solutions.
In addition, the conductive layer may be susceptible to corrosion as a result of using a conventional cleaning solution. Referring to FIG. 2, a conductive layer pattern 30A can be partially etched during the cleaning process, thus potentially deforming the profile of the conductive layer pattern. The corrosiveness of the cleaning solution may reduce the life spans of pipes and other cleaning equipment used in conjunction with the cleaning solutions. Additionally, a separate rinsing process may be required between the application of the cleaning solution and the deionized water rinsing process. As a result, manufacturing processes may become increasingly complex. Since a conventional cleaning solution itself may contain a sizeable number of metal ions and contaminants, the metal ions and contaminants may adhere to the surface of the integrated circuit substrate during the cleaning process.
Thus, there is a need in the art to address the problems associated with conventional cleaning solutions.